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Physics Motivation

According to our present understanding, the early Universe contained the same amount of matter and anti-matter and - if the Universe had behaved symmetrically as it developed - every particle would have been annihilated by one of its antiparticles. One of the great mysteries in the natural sciences is therefore why matter dominates over antimatter in the visible Universe.

The breaking of the combined charge conjugation and parity symmetries (CP-violation, CPV) in the Standard Model of particle physics (SM) is insufficient to explain this and further sources of CPV must be sought. These could manifest themselves in electric dipole moments (EDMs) of elementary particles, which occur when the centroids of positive and negative charges are mutually and permanently displaced. An EDM observation would also be an indication for physics beyond the SM.

Investigations on different systems are required to pin down CPV sources and this proposal aims to lay the foundations for the study of new CPV mechanisms by searching for EDMs of charged hadrons in a new class of precision storage rings. It will develop the key technologies and achieve a first directly measured EDM limit for protons and deuterons and thus provide the basis for a new European flagship research infrastructure.

The EDM measurement principle, the time development of the polarization vector subject to a perpendicular electric field, is simple, but the smallness of the effect makes this an enormously challenging project. A stepwise approach, from R&D for key-technologies towards the holy grail of a double-beam precision storage ring with counter-rotating beams, is needed. The research environment of the Forschungszentrum Jülich (Germany), including COSY, provides the optimum basis for one of the most spectacular possibilities in modern science: finding an EDM as a signal for new physics beyond the SM and perhaps explaining the puzzle of our existence.